By Gavin Jones
ROME (Reuters) - Matteo Renzi looks well placed to regain the leadership of Italy's ruling Democratic Party (PD) on Sunday, but returning to government may be a much tougher task for the former prime minister.
The PD will hold a primary election among its supporters on Sunday and opinion polls suggest Renzi will comfortably beat his two rivals, Justice Minister Andrea Orlando and Michele Emiliano, governor of the southern region of Puglia.
An opinion poll by the Ixe Institute last week suggested he will win close to 60 percent at Sunday's ballot to be held at makeshift polling booths around the country, far ahead of Orlando, seen on 15 percent, and Emiliano on 8 percent.
While Renzi still seems to be the most popular politician among PD voters, the party and his own appeal look much weaker than during his heyday as prime minister, after he failed to convert his ambitious reform agenda into reality.
Renzi's current personal approval rating is about half of the 50 percent he posted three years ago, according to Ixe.
"Renzi's anti-establishment halo is gone and his credibility as a reformer has been dented by his bombastic promises and the relatively modest reforms he managed to deliver," said Wolfgango Piccoli of the Teneo Intelligence think-tank.
Renzi, 42, resigned as prime minister in December after a crushing defeat in a referendum over constitutional reforms aimed at streamlining lawmaking, but he quickly began plotting a comeback from his Tuscan home.
With a national vote due by May 2018, polls show the ruling PD has slipped behind the anti-establishment 5-Star Movement, which questions the country's euro membership. Renzi's ability to counter the 5-Star surge may be crucial in fending off an existential threat to the euro zone.
Polls show 5-Star now has around 30 percent of the vote and a lead of between three and eight points over the PD after a dispute between Renzi's loyalists and left-wing traditionalists caused a party split in February.
As a result of the party split and the muted tone of the campaign, turnout is expected to be far below previous PD leadership primaries, which have always drawn at least 2.8 million people to the polls.
In the only pre-vote debate on Wednesday, Renzi said he would be happy to see a million people turn out to cast a ballot. Anyone over the age of 16 can vote on Sunday if they have Italian residency and declare that they support the PD.
A rare spark in a low-key campaign was when Emiliano was confined to a wheelchair after snapping his Achilles tendon performing a traditional Puglian dance on the hustings.
Separately, the fast-talking Renzi warmly welcomed the victory of centrist Emmanuel Macron in the first round of the French presidential election on Sunday, saying they were both fighting populists and trying "to change Europe".
Orlando, who has criticized Renzi for turning the PD into a one-man show, shot back that if Renzi wins on Sunday he risks the same fate as Benoit Hamon, the French Socialist who won just 6 percent of the vote in the presidential election.
(Editing by Steve Scherer and Catherine Evans)